CFM Calculator
Calculate CFM (Cubic Feet per Minute) for HVAC systems, ventilation, and airflow requirements. Determine proper fan sizing and ductwork for optimal performance.
Step 1: Room Details
Understanding Air Changes per Hour
Air Changes per Hour (ACH) represents how many times the air in a room is replaced in one hour. Different room types require different ACH values for proper ventilation. Residential spaces typically need 2-8 ACH, while commercial and specialized spaces may require 10-30 ACH.
Step 2: Additional Options
About CFM Calculations
CFM (Cubic Feet per Minute) is calculated by multiplying the room volume (length × width × height) by the Air Changes per Hour, then dividing by 60 (minutes in an hour). This gives you the minimum airflow required to properly ventilate the space according to your selected ACH value.
CFM Calculation Results
Required CFM for Proper Ventilation
Air Changes per Hour Comparison
| Room Type | ACH Value | Required CFM | Air Volume per Hour |
|---|
CFM Calculation Breakdown
CFM Calculation Formula
CFM = (Length × Width × Height) × ACH ÷ 60
To calculate CFM, multiply the room dimensions to get the volume in cubic feet, then multiply by the Air Changes per Hour, and divide by 60 (minutes in an hour). For example: 20×15×8 ft room with 6 ACH = (20×15×8) × 6 ÷ 60 = 240 CFM.
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